Can you access emails directly from centurylink's webmail site? Have you recently changed ISP, OS, router, modem, hotspot etc.? Do you have a cell phone or tablet with a separate data plan? If you're using a desktop or laptop, disconnect your usual WiFi and temporarily connect to the hotspot of your mobile device. Does Thunderbird work properly when connected this way?

Clay

Yes I can access my email at centurylink.net. No I haven't changed anything that you listed. I connected my desktop to my mobile "hot spot", but it made no difference. Supposedly tech support at Brightspeed/Centurylink is working on the issue. Haven't heard anything back from them. Back in late April or early May the same thing happened, but it started working again after about 24 hours. No explanation for that temporary outage from Bspeed/Clink. At the same time of that temporary outage, my landline also went down. They (surprisingly) sent a repairman that day. He found 2 breaks in the copper line leading to the house and fixed those breaks. Brightspeed then sent me a device that bypasses the degrading copper lines. It connects me to the nearest cell tower so my landline phone number acts the same way as a cell phone. Are you familiar with this kind of device? Could it be causing a problem? I've been using it since maybe the 2nd week of May.